Originally Posted by
dabac
But permanently riding like that does add some risk.
If, say you're out of the saddle, pushing hard and something in the drivetrain should fail, causing you to come down heavily over the bars, an uncut steerer protruding upwards has greater potential of doing damage than if it's sitting flush with the stem.
Also why it's sensible always to use a top cap, even if it's not strictly required once bearing preload has been set.
Riding with spacers above the stem is no more risky than riding with a flush stem. The top cap can be left in place just as with the stem. I haven't seen too many people running stems without caps and there's no reason to remove the cap if you have spacers above the stem.
I've also experienced many crashes of many different types including a pedal shearing off and a crank breaking and going over the bars. I haven't once come down on top of the stem. It's a small target and there are lots of other things to hit on the way off a bike.
I also don't think anyone is talking about leaving a huge amount of spacers above the stem. An inch would be a lot to leave.